Not osmosis, but you know what I mean). With tube & fin condensors in MVAC applications there is never "too much" airflow. Yes, the 50F diff (160-110F) on the condenser was at idle, and ambient was about 90F. Is there more info needed?THanks -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a, Paul:I had to dig a bit deeper - MB made several running changes in the 1983 123'sThere are actually 4 different circuit diagrams for the A/C system that year - just for your 123.123 I found the R4 reference, and it should have 170 Ml of oil in the system.Your aux fan should run at the ambients you listed. This is an electronic tool that sucks in air through a tube and across a sensor. Lasers don't do well on vent temps, a stick thermometer is better in that application. Gnats & mosquitos will clog deep. SO here's my question. absorb by the evaporator to insure all liquid refrigerant entering the evaporator. Maybe a jerky locker.I cleaned the condensor with the off the shelf ac cleaner stuff from Home Depot that I used on my home evaporator. Use strips of foam to couple the two heat exchangers if necessary.B. The OEM spec is 2300 rpm @ 12.6v (engine stopped fully charged battery). Until 1995, most cars with air conditioning used R-12 Freon refrigerant which has shown to have an environmental impact. The larger line at the expansion valve is the suction line. I've got a ball valve I'm going to put in the coolant line before the coolant goes through the firewall to the core. ). -------------------------"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest." Table 1 summarizes the technical characteristics of three potential R134a alternatives. That is for the compressor, drier, expansion valve and condenser. The difference between R12 and r134a is the BTU carrying capability. R1234yf is more environmentally friendly and has a global warming potential of 4. To prevent refrigerant loss you should consider replacing your old hose lines with barrier type hose. The original rubber a/c hose lines in your car will leak out R12 through the hoses lining. difference between r12 and r134a expansion valvewarning signs for a deteriorating patient with covid 19 infection 2022.07.03 18:36 18:36 I dont know why the cost difference between compressors is so huge, though. R12 is highly destructive to the earths ozone layer. R134a Refrigerant Recharge Kit with BPV31 Bullet Piercing Valve and R134a Quick Coupler, R134a/R-12/R-22 Freon Refrigerant Hose Can Tap Kit for A/C System - Easy to use. On the other hand, R12 has a global warming potential of 10,910. Flush with a garden hose - do not use a high pressure washer - you can bend the fins flat & damage the condensor.B. You are indeed 20% out of the OEM spec for cooling. I'm just trying to help you avoid headaches in the long run. Generally, the new amount is 75-85% of the quantity advised by the manufacturer. difference between r12 and r134a expansion valve . Questions About Becoming A Professional Member? The original CFC expansion valve used for R12 needs to be replaced with an HFC one for 134a to feed the evaporator correctly. However, you can convert R12 to R134a by yourself, save money and keep all the tools purchased. If liquid refrigerant were to exit the evaporator. R134a refrigerant is about 10% less efficient in moving heat than R12! Is that why expansion valves are specific to R12 or R134A? Consider using the newer valve, even with 134a stamped on the valve. This refers to BTU's (heat) moved per pound of refrigerant moved. I could easily be over at least 2 - 3 ounces over on the oil. In 1994 they switched from R-12 to R-134a. There are two hoses listed, R-12 64-53-1-377-821 for $72.50, and R-134a 64-53-8-391-051 fro $262.50. But as there's not a big difference, people say you can suffice with either. 34 in 70 series w/ R12 in 100+ Tucson, AZ summer heat w/ hd-t, w/ 13B-T is was unbearable about 31 at vent w/ R12. I think the way to go here is1. Edited: Tue July 17, 2007 at 3:25 AM by bohica2xo, I believe there is only one switch - the refrigerant switch. The current expansion valve is FF - 1/4 - C. Is it neccesary to replace this valve? . Autor de l'entrada Per ; Data de l'entrada calexico west port of entry hours; 12 month libor rate 2021 a difference between r12 and r134a expansion valve a difference between r12 and r134a expansion valve But, if your old compressor has lock-up or if your current expansion valve is not functional it would wise to replace the expansion valve with a valve designed for R134a. VerticalScope Inc. All Rights Reserved. By using a qualified a/c shop with the proper equipment you odds are in your favor of having the job done correctly the first time. Helical and Serpentine coils. So that indicates it is cooling well there doesn't it? Its highest value is 1. Note that passwords are case-sensitive. R12 Expansion Valve = 201 830 06 84 R134A Expansion Valve = 201 830 04 84 Is there a difference after all? Answer: OK, I'll bite. Hence, the effect of R12 on global warming is up to 10,000 times higher than carbon dioxide. There is a lot of differences between the R12 and the R134a fittings, you can't mistake them. As R134A refrigerant has different operating characteristics and pressures this valve is not necesssry. This drop can affect energy consumption since the plant will operate for a longer period or a larger plant will have to be installed. link to How to cut off a Catalytic Converter. Components Coils, Heaters, Motors, etc. Later model cars that come with 134A will have 134A only connectors. R-12 is no longer used or produced in many countries and remaining quantities have skyrocketed in price. A slow loss of cooling at city speeds is usually related to condensor capacity & airflow issues. Below are the major differences between R134a and R12: Chemistry The chemical composition of R12 and R134a differ. Trinary Pressure Switch quantity. I don't have the FSM matrix handy for that 123.123, but a 123.133 shows a test rpm of 2,000 - and vent temps between 54f & 66f at 91f to 95f ambient. We chose to use 5-6 ounces of oil to be on the safe side: 3-4 ounces for the compressor, 1 oz of oil for the drier and another ounce of oil for system losses. You may need to adjust the valve in a bit to get desired superheat. Trinary Pressure Switch $ 39.99. I bought a relay to put on it connected to the compressor clutch. Spray it deep, and let it sit for a few minutes. In this study, without the need for major modifications to the bus air conditioner, the variation of the ejector dimensions according to different parameters has been investigated in the case of using the R1234yf, R1234ze(E), or R600a refrigerants, which may be a substitute for R134a as a refrigerant due to . This means that it has a high potential of causing depletion to the ozone layer. R134a vs R12 refrigerant? had writing on the side that said R134a. 10,000BTU conduction heating? Miscibility with oil: R12 can be mixed with the compressor oil no matter the operating condition. In sum, R12 has done more bad than good. shown for the parallel flow, aluminum condenser that is listed. Unfortunately, the R12 refrigerant doesnt always blow cold air. The P H and T cond,sat of the HR12 at a T oa of 40 C were higher than that of the R134a, resulting in a higher P e than that for the R134a. You'll get marginally better performance out of the change as the expansion valve is matches the refrigerant characteristics. 4.3 out of 5 stars 491. ~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446. R134a has a smaller molecule than R12 so R134a will leak out sooner than R12. It's actually a reaction with chlorine in the mineral oil that may have been absorbed and leftover from the old R-12. These two refrigerants are the older types and are not used in newer refrigeration and air conditioning systems. At 2000rpm, windows open, highest fan, hi pressure stabilized at 225 psi, low 25psi.Ambient 81F, vent 61F. Well, I'm not sure it is 'fine' - it doesn't cool very well in 95F weather. When I compare parts, 93 uses one part number and 94 has a different part number. There is more to check.The evaporator must be clean as well as the condensor - was this a smoker's car?You should check the water control valve for the heater core. The MB chart shows 360 psi with R12 in some conditions. Inasmuch as R134a has a global warming potential thats over 1000 times more threatening than carbon dioxide, its better than R12. El juny de 2017, el mateix grup va decidir crear un web deDoctor Who amb el mateix objectiu. But, what is considered a good temperature differential across the condensor? Post photos, respond to polls and access other special features. R12 can move more heat than r134 so when it isn't very hot and the system isn't maxed out you wont be able to tell the difference but when its 110 out and the inside is 140 R12 will cool the cabin temp faster. I'm having the same concern. is good, then I should be looking elsewhere? Hopefully after you have read this entire page you will have enough information to determine which type of refrigerant is best for you. Besides, R134a refrigerant was manufactured after R12 was banned to help reduce the harshness of the old chemical (R12) on the ozone layer. James10952001. Stay home and grill your own steaks and stir your own martini. The sticker typically has a place to note the amount of refrigerant used, the type of oil and amount of oil, the technicians sign off or name and the date of the conversion. I don't think it has any air dams or seals, I'll check to make sure. Some cars have both an engine coolant temp switch & a refrigerant temp switch, others only the refrigerant switch. Lets take you through the advantages, disadvantages, and differences of these two refrigerants a detailed comparison including R12 vs R134a performance. Replace the drier with a drier that has a desiccant that is R134a compatible, use new R134a o-rings. The problem with these so called drop in replacements is that to properly handle them you may need dedicated equipment to identify the gas and evacuate it for proper disposal. Safety: R134a is safe to use as its non-flammable and cant explode. ing the expansion valve, a maximum opening superheat of 7F, and a standard factory air test superheat setting. After the system has been tested out it should be checked for leaks. I'm thinking I might have put too much oil in the system - everywhere i read had a different amount - the manufacturer of the compressor, the MB factory service manual, online forums. The analysis focuses on Coefficient of Performance for . So to keep things simple and to avoid controversy and politics we have R134a. Low refrigerating effect per pound: In comparison to other refrigerants, the refrigerating effect of R12 per pound is low. With R134a you do not rely on the site glass. So if you car has a large amount of rubber hose, such as a 40 feet with the 911, then you will be re-charging the system often and that is expensive no matter which refrigerant you use. What is needed? If it splashes inside the eye, it could lead to a serious eye problem. By after changing just about everything, he got what was termed, satisfactory cooling. I'm not sure. R134a compressors are substituted as new to retrofit the R12 system compressor part numbers with different height sealing washers. All fans must work at 100% of the OEM rating. I'm curiousSo there is work to do, ie performance should be able to be improved. You will be fine with a 134a-compatible TXV running R12. The experimental values of C.O.P.H obtained with the R134a/ester charge were 20.2% In practice this means that the car can overheat and the aux fan will stay off! By noting the ambient temperature you can look up what the preferred high side pressure should be. If your car does not have a high pressure cut-out switch in the AC system then youll need to have one installed (call us if you need help). There are other refrigerants: some of which may work, some of which dont work, some of which will destroy your a/c system and some of which are dangerous. So, instead of using R12, other better options include R401b, R134a, R401a, etc. Therefore, its most suitable for both commercial and domestic environments. Rich Membership Chairman Using R134a in an R12 system will cause the oil not to move with the refrigerant, causing a system failure and probably won't even cool the system well, if at all. Als nostres webs oferimOne Piece,Doctor Who,Torchwood, El Detectiu ConaniSlam Dunkdoblats en catal. The general practice of charging the system with 15% less refrigerant adds to the thermal deficiency of R134a. Further production of R12 was banned in some developed countries by the Montreal Protocol because of its harsh effect on the ozone layer. You do not need to replace the expansion valve in most cases. R12 was once used in many air conditioning units as a refrigerant or cooling agent. And by matching the correct amount of R134a to use in a given vehicle, correcting the superheat of the expansion valve (if necessary), you can in some manner nearly balance or match the amount of heat drawn out by the evaporator and released by the condenser. R134a requires a different oil. I've straightened the fans I can and sprayed simple green on it, let it soak then hosed it down well. I have the original (R12) style expansion valve in the Maverick AC system. It won't be optimal, though.On some/many valves, you can adjust them, but that might make matters worse unless you really know what you're doing (which I don't!).RegardsGeorge. I have just bought gauges. R12, on the other hand, has an ozone depletion potential of 1, implying that it can damage the ozone layer. Also, R134a cylinders are light-blue in color. The aux fan didn't switch on though and I didn't check the high side temperature. We recently created this blog site to enable us to share our knowledge with other automotive mechanics and car owners. maintain the A/C of older cars. The mechanical fan & clutch should be checked as well. All pre-97 XJs use systems with the same basic operating principle, although the parts do change a bit. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a, Hi pdrayton- If you can remember the oil capacity that you found in all your research and post that, then bohica and others can have a better idea if you have too much; see if you can find that info! R134a is the most widely accepted alternative automotive refrigerant used to replace R12. This is the part that controls the system pressures. R12 is heavier than R134a and has smaller molecules. Thomas Jefferson, Thanks,OK, I'm starting to feel a little better about it. Also called the orifice tube. Don't like the sound of custom parallel condensor. I am ordering new parts, and planning to convert my system to R-134a. Therefore, the R12 refrigerant is illegal, and emitting it is illegal. This refers to BTU's (heat) moved per pound of refrigerant moved. The condenser water inlet temperature and flow rate are controlled with the use of a . Bookmarks: Digg; del . Read on for more information about using automotive r134a in a refrigerator and vice versa. R134a has the chemical formula CF3CH2F and is known as tetrafluoroethane. The reason is that the vehicles, for instance, manufactured currently configure the engine for R1234yf refrigerant, making no provision for replacement. Also, if you want to know what happens if you put R134a in an R12 system, you should first confirm if the R12 system can be replaced or if the refrigerants can be mixed. You can spend long evenings reading about the differences between the two refrigerants. Since 2010, all home AC systems manufactured use a refrigerant like R134a that has zero ozone depletion potential (ODP). The difference between the two is about 10,000 btu/h. It is made up of carbon, hydrogen, and fluorine. I recommend replacing the expansion valve when you do the swap. Compared with the cost-performance ratio, R507 is 30-40% . Skin contact: If the R134a (liquid) comes in contact with your skin, it could cause a burn. Before landing on the debate of R134 vs R12 you should know that both R134a and R12 are AC refrigerants types used in refrigeration and air conditioning systems. The common problem when converting from R12 to R134a is lack of knowledge or equipment. Paul -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a. As an example, let's say the R12 charge specification is listed at 2 lbs. I'm also thinking maybe I should go to R134 - it might work better with the right amount of oil and the correct expansion valve. The value of carbon dioxide is 1. Quick View. Pray I can let some oil out of the compressor without losing my precious R12. -------------------------1983 Mercedes 240D on R12 and WVO!1192 Mercedes 300D 2.5 R134a1993 Toyota Pickup converted to R134a, Bohica, You say the drop in performance is not linear with too much oil. Took me a while to figure that one out, and how to say that. As for R134a and R1234yf, theres no room for conversion. Please enter a valid email address for yourself. By using a black light the dye will glow in areas where oil leaks are visible. Large temperature difference between expansion valve inlet and outlet oReplace expansion valve Air . But, if your car lacks enough condenser and you have many 100+ degree days then you may want to stick either increase air flow, add another condenser as we mentioned in The Mr. Ice Project or stick with R12. AFAIK, there is no clutch on the engine fan on the 240D. You do not want to exceed the systems high side recommendations. These efforts to balance the system can not be realized if there are problems within the a/c system, such as: poor performing compressor, dirty condenser or poor air flow through the condenser, malfunctioning expansion valve, water or air in the system, improperly operating fresh air or heat input in the climate-air mixing system. ambulance tailgate conversion I cleaned the evap as best I could, if that is what you are getting at. The original expansion valves work very well with R134a. The aux fan seems to be working fine - it switches on occassionally. Your old hoses of course will not fit. If ambient is 90 (today) and the output of the condensor is 110, that's pretty good isn't it? At 40, it is 35psi, which is a difference of 8.9psi. If you find any of these conditions you will want to liquid flush (with dedicated AC flush solution) all the lines, condensers, evaporator (remove the expansion valve) before you proceed further. The expansion valve is designed so that the temperature of the refrigerant at the evaporator outlet must have 8 to 12F (4 to 7C) of superheat before more refrigerant is allowed to enter the evaporator. Thread starter goldNSX; Start date 1 August 2009; Tagged . The oil used in R12 systems is not compatible with R134a refrigerant. A. Pressure/temperature table for R12, R134a, and R513A is shown in Figure 1. . The chemical composition of R12 and R134a differ. If you you dont have the free time to play then you are better off to pay a technician. Though I have seen em run as cold as 12 deg F. If the thermo switch is malfunctioning. Break out the new gauges and measure hi and lo at 1500rpm, and do the Merc FSM test to see how we're doing performance wise. The cure is to use the newer R134a compressors is sealing washers that are different thickness. The ARPA Zone/Open Membership Discussion Forums. You can use this space to go into a little more detail about your company. 30 deg is pretty coldSystems generally run between 40 and 43 deg. This chart has a column of ambient (outside) air temperatures on one side and a corresponding range of high side pressures on the other side. With that said, I would source the TXV from another source such as NAPA just to avoid any problems. It slowly gets warmer and warmer in the car, even at highway speeds. R12 is used in several applications like low temperature, medium temperature, and high-temperature applications. You'll want the expansion valve matched to whatever refrigerant you're using. However, theyre still used in older plants, systems, and the automotive industry. R12 is otherwise called dichlorodifluoromethane is a colorless gas (chlorofluorocarbon halomethane (CPC) that is used as an aerosol spray propellant and a refrigerant, and is soluble in organic solvents. 5. Is it exponential, squared? This is because R134a. If the system was upgraded by a professional it should have an upgrade sticker. The cable is adjustable at the valve arm. Some say that a chemical reaction can harm the A/C very badly as R134a reacts with mineral oil in some way.